Herd Protection Seen With 4-Valent HPV Vaccination

2006 to 2017 saw increase in vaccination; drop seen in HPV detection in vaccinated, unvaccinated

WEDNESDAY, Jan. 23, 2019 (HealthDay News) -- From 2006 to 2017, there was a decrease in 4-valent vaccine-type human papillomavirus (HPV) detection among vaccinated and unvaccinated women, according to a study published online Jan. 22 in Pediatrics.

Chelse Spinner, from the University of Cincinnati, and colleagues determined the proportion of vaccinated and unvaccinated women who were positive for vaccine-type HPV across studies that recruited women aged 13 to 26 years from hospital-based and community health clinics from 2006 to 2017.

The researchers observed an increase in vaccination rates from 0 to 84.3 percent, and 97 percent of participants received the 4-valent vaccine. Detection of the 4-valent vaccine-type HPV decreased 80.9 percent among women who were vaccinated, from 35 to 6.7 percent (odds ratio, 0.13). There was a 40 percent decrease in 4-valent vaccine-type HPV detection among women who were unvaccinated, from 32.4 to 19.4 percent (odds ratio, 0.50). In waves 3 (2013 to 2014) and 4 (2016 to 2017), the estimated vaccine effectiveness was 90.6 and 80.1 percent, respectively.

"The significant decrease in 4-valent HPV types among women who were unvaccinated suggests herd protection," the authors write. "Although these findings are important for clinical care and public health policy, continued surveillance will be important to assess for waning vaccine effectiveness, herd protection, and the impact of 9-valent vaccine introduction."

Two authors disclosed financial ties to the pharmaceutical industry, including companies involved with HPV diagnostics.